// 导航栏滚动效果
window.addEventListener('scroll', function() {
  const navbar = document.getElementById('navbar');
  if (window.scrollY > 20) {
    navbar.classList.add('scrolled');
  } else {
    navbar.classList.remove('scrolled');
  }
});

// 用户菜单切换
const userMenuBtn = document.getElementById('userMenuBtn');
const userMenu = document.getElementById('userMenu');
